Adult fungus gnats are fairly easy to control. It becomes more difficult with the larvae, especially if you do not want to use chemical agents. Read what you need to know about the prevention and control of sciarid gnats in the following text.
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You can see gray-brown, 3 to 4 mm tall, narrow mosquitoes that crawl over the surface of the earth in the flower pot. However, they also fly around and slowly and gently settle down on leaves. They resemble fruit flies. Each female lays between 100 and 200 eggs, from which the larvae hatch after a week. These are up to 5 mm long, maggot-shaped, whitish in color and have a black head. They live in the soil and can damage the plant in the process. The plants weaken. You can't really find a cause, except for the little flying insects.
Prevent
Prevention is difficult and even if it is successful, infestation cannot be ruled out. The pests are often brought in when you buy a new plant or with fresh potting soil. It makes no difference whether you buy cheap or expensive soil. Even in organic soil, the eggs are, which is because the different types of fungus gnats are quite useful. This is why they are particularly common in organic farms. The mosquitoes like to settle when the plants are outside in summer. However, it doesn't do much to leave them in the room, because fungus gnats can also get into rooms through open windows. Individually they are hardly noticed, but when they have multiplied and appear en masse, they become annoying, because they do not only stay on the plants, they fly around everywhere.
It is important not to keep the houseplants too moist. The top layer of soil must not be constantly damp. Sciarid gnats love that. The earth can therefore preventively with sand, small stones, small shells or the like Materials to be covered. The sand layer should be about 1 cm thick. Quartz sand is particularly suitable.
Tip: Planters with an irrigation system are good for plants that need some moist soil. Once grown in, the plants draw the required water from the reservoir from below, the upper layer of soil hardly ever comes into contact with water and remains nice and dry.
It is also helpful to treat new potting soil with heat in the microwave or in the stove. Insect eggs are killed in the process. Depending on the amount and wattage of the microwave, the earth should be heated for 2 to 5 minutes. In the oven, the earth is spread out on a tray and heated at 100 degrees for about 1 half hour. Larvae are killed, regardless of the species.
However, it is even better not to use any soil at all in the usual sense. With hydroponics you save yourself sciarid gnats, at least as far as possible. Not all plants are good for this, but there are a lot. Regardless of whether seramis, gravel, perlite or other mineral substrates are used, fungus gnats cannot multiply in them. The condition is that all potting soil has been removed when repotting. Dead root parts and dead organic material must also be removed.
It can also help not to water the plants standing in potting soil from above, but always from below, i.e. in the planter or a saucer. About 30 minutes after watering, however, excess water should be poured off.
Fighting adult fungus gnats
Adult fungus gnats are fairly easy to control. You like strong colors, especially yellow. Therefore, non-toxic yellow stickers or Yellow panels. You put them in the soil of the infested flower pot or set them up in the immediate vicinity. The mosquitoes settle on the sticky surface and can't get away. If the infestation is severe, the
Stickers are changed from time to time, whenever they are almost full, there is not much space left for new pests. It is important to leave the stickers or boards in place for weeks so that the next generation is also eliminated. If the infestation is severe, the mosquitoes can also be vacuumed away. The control is important so that no eggs are laid and new generations grow up.Fight sciarid fly larvae
The larvae can be controlled in different ways. From old home remedies to chemical insecticides, the options are numerous. Sometimes several have to be tried out, not all of which are effective.
Home remedies
The trick with matches is old, but it usually works quite well. A few matches are simply stuck upside down in the potting soil. The ignition head contains sulfur components that kill the larvae in the soil. To do this, however, the matches have to be replaced after a few days. In addition, you have to keep the soil drier. A neat layer of sand on the ground is also useful, as it prevents adult animals from laying eggs further.
A mixture of lukewarm water, baking powder, a little oil and a little salt is also helpful. This mixture is sprayed directly onto the infested soil. After that, the flies no longer dare to go to the vessels.
Completely sealing off the potting soil for 4 to 5 weeks helps against the adult animals and the larvae. The best way to do this is to put the whole flower pot in a pearl stocking and seal it tightly. The water drainage holes also need to be. So no flies come to the earth to lay eggs and no newly hatched larvae come out of the earth. Since a cycle lasts 4 to 5 weeks, there should be rest afterwards.
Coffee grounds and co
The even distribution of coffee grounds on the surface of the potting soil has also proven to be extremely effective in the past. Another extremely effective trick is placing matches (upside down) in the ground.
After only two to three days, the infestation with the little pests is a thing of the past. The use of fruit fly traps in particular has always enjoyed great popularity. A special fruit fly cocktail (a mixture of organic acids and fruit juice) is poured into the fly trap, whereupon the small insects are attracted and crawl into it.
The special design of the fruit fly trap makes it impossible for the flies to fly out or crawl out. This means the end of the little flies.
Parasitic nematodes
Nematodes are tiny roundworms, tiny, barely noticeable to the eye. They are brought into the earth with the irrigation water. There they attack the larvae of the fungus gnat as parasites and kill them. Nematodes are harmless to humans and animals. Hundreds of thousands of these nematodes can be ordered by mail order. They are now also available in plant markets, but also only to order. It usually takes 2 to 3 weeks to resolve the problem. Steinernema feltiae are best suited. If the infestation is severe, the treatment should be repeated after about 4 weeks. It is important that the treatment is not carried out in the sun, because nematodes are sensitive to light. In addition, the substrate may be used during the treatment time, i.e. approx. 4 weeks, do not dry out, otherwise the nematodes will die. But the earth shouldn't be too wet either.
bacteria
Microorganisms, especially bacteria, can be valuable helpers in the fight against sciarid gnats. The bacterium Bacillus thuringiensis var. israelensis (BTI) forms permanent spores with protein crystals, which are poisonous for the larvae of the fungus gnat. The bacteria can be acquired like nematodes and they too are added to the irrigation water. They are absolutely harmless, except for the larvae.
Predatory mites (Hypoaspis miles)
Predatory mites feed on the larvae of the fungus gnat. Their use in greenhouses and closed winter gardens is particularly advantageous. Predatory mites live in the upper layers of the soil. There they hunt the larvae and eat them. This usually goes on until there are no more. Even then, the predatory mites can still exist for a few weeks.
chemistry
Particularly desperate plant lovers use a mosquito repellent that is used in ponds and other stagnant bodies of water. This added to the irrigation water kills the pests. There are also biological remedies, you have to take a closer look when buying.
Chemistry should always be only in emergencycan be used. There are different insecticides on the market. You should get advice on which ones are currently up to date. Funds are withdrawn from the market every year and new ones are used for them. Hopefully, qualified staff is familiar with the advantages and disadvantages, otherwise you have to compare it yourself. It is important to adhere to the manufacturer's instructions for dosing.
Sciarid gnats are usually just uncomfortable and not particularly dangerous for plants, unless they are young plants, seedlings or cuttings. It is important to get rid of the fungus gnats yourself and, above all, the larvae. Yellow stickers are very helpful. In addition, the plant substrate should be kept drier and sprinkled with a layer of sand. If nothing helps, nematodes, bacteria or predatory mites are good biological control measures.
